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Leedsichthys
|Row 3 title = Family |Row 3 info = Pachycormidae |Row 4 title = Genus |Row 4 info = Leedsichthys |Row 5 title = Species |Row 5 info = * L. problematicus (type) }} Leedsichthys was a giant pachycormiform actinopterygian fish that lived during Middle Jurassic period,Liston, 2004 and is known from the Callovian Oxford Clay Formation. The generic name Leedsichthys means "Leeds' fish", after the fossil collector Alfred Nicholson Leeds, who discovered it before 1886 near Peterborough, England. The fossils found by Leeds gave the fish the specific epithet problematicus, because the remains were so fragmented that they were extremely hard to recognize and interpret. The remains of Leedsichthys have been found in the Callovian of England, northern Germany and France, the Oxfordian of Chile, and the Kimmeridgian of France.Liston, 2008a Discovery and assignment of name During the 1880s, the gentleman farmer Alfred Nicholson Leeds collected large fish fossils from loam pits near Peterborough, England. In May 1886 these were inspected by John Whitaker Hulke, who in 1887 partially reported them as the back plates of the stegosaurian Omosaurus.3 On 22 August 1888, the American dinosaur expert Professor Othniel Charles Marsh visited Leed's farm at Eyebury and quickly concluded that the presumed dinosaurian armour in fact represented the skull bones of a giant fish. Within two weeks British fish expert Arthur Smith Woodward examined the specimens and began to prepare a formal description published in 1889.4 In it he named the species Leedsichthys problematicus. The generic name Leedsichthys means "Leeds' fish", from Greek ἰχθύς, ichthys, "fish".2 The fossils found by Leeds gave the fish the specific epithet problematicus, because the remains were so fragmented that they were extremely hard to recognize and interpret.2 After a second publication in 1889,5 objections were raised against the perceived "barbaric" nature of the generic name, which simply attached a non-Latinised British family name to a Classical Greek word. Woodward therefore in 1890 changed the genus name to Leedsia, resulting in a Leedsia problematica.6 However, by modern standards this is a non-valid junior synonym.2 The holotype specimen, BMNH P.6921, had been found in a layer of the Oxford Clay Formation, dating from the Callovian, about 165 million years old. It consists of 1133 disarticulated elements of the skeleton, mostly fin ray fragments, probably of a single individual. Another specimen, BMNH P.6922, contains additional probable fragmentary remains of Leedsichthys. Woodward also identified a specimen previously acquired from the French collector Tesson, who had in 1857 found them in the Falaises des Vaches Noires of Normandy, BMNH 32581, as the gill rakers of Leedsichthys. Another specimen bought in 1875 from the collection of William Cunnington, BMNH 46355, he failed to recognise.7 Leeds continued to collect Leedsichthys fossils that subsequently were acquired by British musea. In March 1898, Leeds reported to have discovered a tail which he on 17 March 1899 sold for £25 to the British Museum of Natural History, which exhibited it as specimen BMNH P.10000; a new inventory number range was began for the occasion.8 Already in July 1898, the front of probably the same animal had been bought, BMNH P.11823. On 22 July 1905 specimen BMNH P.10156 was acquired, a gill basket. In January 1915 Leeds sold specimens GLAHM V3362, a pectoral fin, and GLAHM V3363, the remainder of the same skeleton with 904 elements, to the Hunterian Museum of Glasgow.2 Leeds had a rival, the collector Henry Keeping, who in 1899 tricked pit workers into selling dorsal fin rays by misinforming them that that Leeds had lost interest in such finds. Keeping again sold these to the University of Cambridge where they were catalogued as specimen CAMSM J.46873. In September 1901, they were examined by the German palaeontologist Friedrich von Huene, who identified them as tail spikes, Schwanzstacheln, of Omosaurus,9 the second time Leedsichthys remains were mistaken for stegosaurian bones; Leeds himself was able to disabuse von Huene the same year.2 In 2001 students at the Star Pit discovered a major new British specimen that they nicknamed "Ariston" after a 1991 commercial for the Indesit Ariston washing machine that claimed it went "on and on and on" — likewise the bones of Leedsichthys seemed to endlessly continue into the face of the loam pit.10 From 2002 until 2004 "Ariston" or specimen PETMG F174 was excavated by a team headed by Jeff Liston; to uncover the remains it was necessary to remove ten thousand tonnes of loam forming an overburden of fifteen metres thickness.1112 The find generated considerable media attention, inspiring an episode of the BBC Sea Monsters series, "The Second Most Deadly Sea", and a Channel Four documentary titled "The Big Monster Dig", both containing computer-generated animated reconstructions of Leedsichthys. Liston subsequently dedicated a dissertation and a series of articles to Leedsichthys, providing the first extensive modern osteology of the animal.13 Apart from the British discoveries finds of a more fragmentary nature continued to be made in Normandy, France. In July 1982 Germany became an important source of Leedsichthys fossils when two groups of amateur palaeontologists, unaware of each others' activities, began to dig up the same skeleton at Wallücke. Remarkably, parts of it were again incorrectly identified as stegosaurian material, of Lexovisaurus.14 From 1973 onwards, fragmentary Leedsichthys fossils were uncovered in Chile. In March 1994, a more complete specimen was found, SMNK 2573 PAL. In 1999 the Chilean finds were named as a second species, Leedsichthys notocetes, the "Southern Sea Monster".15 However, Liston later concluded that the presumed distinguishing traits of this species, depressions on the gill rakers, were artefacts caused by erosion;13 Leedsichthys notocetes would be a junior synonym of Leedsichthys problematicus. Fossil range The fossil remains of Leedsichthys have been found in the Callovian of England and northern Germany, the Oxfordian of Chile, and the Callovian and upper Kimmeridgian of France.17 These occurrences span a temporal range of at least five million years. Size .]] Unfortunately, although the remains of over seventy individuals have been found, these are usually partial and fragmentary. This has made it difficult to estimate its length. Arthur Smith Woodward, who described the specimen in 1889,Smith Woodward, 1889 estimated it to be 30 feet (around 9 metres) long,Smith Woodward, 1905 by comparing the tail of ''Leedsichthys with another pachycormid, Hypsocormus. In 1986, Martill compared the bones of Leedsichthys to a pachycormid that he had recently discovered,Martill, 1986 but the unusual proportions of that specimen gave a wide range of possible sizes. More recent estimates, from documentation of historical findsListon & Noè, 2004 and the excavation of the most complete specimen ever from the Star Pit near Whittlesey, Peterborough,Sloan, 2004Liston, 2006 support Smith Woodward's figures of between 9 and 10 metres. Recent work on growth ring structures within the remains of Leedsichthys have also indicated that it would have taken 21-25 years to reach these lengths,Liston, Steel & Challands, 2005 and isolated elements from other specimens indicate that a maximum size of just over 16 metresListon, 2005 is not unreasonable. Like the largest fish today, the whale sharks and basking sharks, Leedsichthys problematicus derived its nutrition using an array of specialised gill rakers lining its gill basket to extract zooplankton from the water passing through its mouth and across its gills. There is little direct evidence for predation as opposed to scavenging on Leedsichthys remains, but specimen P.6924 in the Natural History Museum of London shows signs of bites from a Liopleurodon-sized pliosaur. These bites have then healed, indicating that Leedsichthys could even escape the top predator of the Oxford Clay seas, probably as a result of its powerful tail. Phylogeny Footnotes References *Haines, Tim & Chambers, Paul. (2006). The Complete Guide to Prehistoric Life. Canada: Firefly Books Ltd. *Liston, JJ (2004). An overview of the pachycormiform Leedsichthys. In: Arratia G and Tintori A (eds) Mesozoic Fishes 3 - Systematics, Paleoenvironments and Biodiversity. Verlag Dr. Friedrich Pfeil, München, pp 379-390. *Liston, JJ (2008a). Leedsichthys des Vaches Noires au peigne fin (translation by M-C Buchy) L’Écho des Falaises (=Ech.des Fal.) No.12: 41-49, 2008 ISSN 1253-6946. *Liston, JJ (2008b). A review of the characters of the edentulous pachycormiforms Leedsichthys, Asthenocormus and Martillichthys nov. gen. In: Mesozoic Fishes 4 Homology and Phylogeny, G. Arratia, H.-P. Schultze & M. V. H. Wilson (eds.): pp. 181-198, 10 figs., 1 tab. © 2008 by Verlag Dr. Friedrich Pfeil, München, Germany – ISBN 978-3-89937-080-5. *Liston, JJ & Noè, LF (2004). The tail of the Jurassic fish Leedsichthys problematicus (Osteichthyes: Actinopterygii) collected by Alfred Nicholson Leeds - an example of the importance of historical records in palaeontology. Archives of Natural History 31: 236-252. *Sloan, C (2004). Big Fish Story. National Geographic Magazine, p.42. 1/9/2004. *Liston, JJ (2006). From Glasgow to the Star Pit and Stuttgart: A short journey around the world's longest fish. The Glasgow Naturalist 24: 59-71. *Liston, JJ, Steel, L & Challands, TJ (2005). Lured by the Rings: Growth structures in Leedsichthys. In: Poyato-Ariza FJ (ed) Fourth International Meeting on Mesozoic Fishes - Systematics, Homology and Nomenclature, Extended Abstracts. Servicio de Publicaciones de la Universidad Autónoma de Madrid/UAM Ediciones, Madrid, pp 147-149. *Liston, JJ (2005). Homologies amongst the fragments: searching for synapomorphies in shattered skulls. In: Poyato-Ariza FJ (ed) Fourth International Meeting on Mesozoic Fishes - Systematics, Homology and Nomenclature, Extended Abstracts. Servicio de Publicaciones de la Universidad Autónoma de Madrid/UAM Ediciones, Madrid, pp 141-145. *Smith Woodward, A (1889). Preliminary notes on some new and little-known British Jurassic fishes. Geological Magazine Decade 3 Volume 6: 448-455. *Smith Woodward, A (1905). A Guide to the Fossil Reptiles, Amphibians, and Fishes in the Department of Geology and Palaeontology of the British Museum (Natural History). Eighth edition. British Museum (Natural History), London. Pp xviii, 110 pages. *Martill, DM (1986). The world's largest fish. Geology Today March-April: 61-63. External links * For more on the Star Pit dig of 2002-2003 look here and also here where the dig was featured in the BBC-Open University series Fossil Detectives. * [http://www.paleocreations.com For a more accurate reconstruction of Leedsichthys visit Paleocreations.] The artist went on to produce the most accurate reconstruction of Leedsichthys to date, which was used on 'Fossil Detectives' (see above). * [http://www.bbc.co.uk/science/seamonsters/factfiles/leedsichthys.shtml The profile of Leedsichthys problematicus from the BBC series Sea Monsters] *"Biggest Fish Ever Found" Unearthed in U.K. National Geographic News. Published October 1, 2003. * [http://news.nationalgeographic.com/news/2003/10/1001_031001_biggestfish.html An article on the latest discovery of a Leedsichthys problematicus fossil], estimated 22 meters = 72 feet (22 m) long} long * [http://www.bbc.co.uk/science/seamonsters/factfiles/images/leedsichthys1.jpg A picture of Leedsichthys problematicus] * [http://scienceblogs.com/tetrapodzoology/2009/07/biggest_ever_fish_has_been_revised.php An article on Leedsichthys from Darren Nash] Category:Amiiformes Category:Prehistoric fish of Europe Category:Jurassic fish Category:Ray-finned fish Category:Prehistoric fish of South America